1. Technical Field
The present invention relates to a spectacle lens selection method for selecting a spectacle lens from a plurality of types of spectacle lens including a distance portion, a progressive corridor, and a reading portion with the distance portion having different sizes from narrow to wide. The present invention also relates to a system for selecting the spectacle lens.
2. Related Art
Spectacle lenses are classified into single-vision spectacle lenses and progressive-power spectacle lenses. A progressive-power lens includes a distance portion located in an upper portion of the lens and provided to view a distant object, a reading portion located in a lower portion of the lens and provided to view a near object, a progressive corridor which is located between the distance portion and the reading portion and where the power continuously changes, and other portions called “sideways portions” or “peripheral portions.”
The distance portion, the progressive corridor, and the reading portion are designed based on wearer optometry information, frame information, spectacle lens information, and other information, and a variety of spectacle lenses are designed in accordance with such conditions and other conditions associated with individual wearers.
To design such a spectacle lens, there has been a spectacle lens design method of related art in which information from an eyeball motion measurement unit is used along with software to analyze a path along which an eyeball of a person wearing spectacles moves so that at least one eyepoint or an average area thereof is identified, and a standard lens is corrected based on the identified information to form a custom spectacle lens that suits the specific eye of the person (JP-T-2008-521027, the term “JP-T” as used herein means a published Japanese translation of a PCT patent application).
There has been another method of related art for providing frame selection guidance and recommending optimum lens design selected from a plurality of types of known lens. In the method, values provided from a head tracking system and statistical analysis results obtained by using a spectacle wearer action statistical model are used to determine a visual action pattern of an individual spectacle wearer (JP-T-2003-523244).
In the related art described in JP-T-2008-521027, in which an eyeball motion measurement unit provides information on the motion of an eye and the head, which is then analyzed by using software, it is not clear how the measured motion of the head and the eyeball of an individual wearer is used in lens design in accordance with the application of the lens. In particular, the fact that many factors involved in designing a progressive-power spectacle lens are not clearly prioritized does not ensure that rational lens design can be performed. Further, use of an eyeball motion measurement unit disadvantageously increases the cost as a whole.
In the related art described in JP-T-2003-523244, it is not clear, as in JP-T-2008-521027, how information on the motion of the head and an eye of an individual wearer is used in lens design in accordance with the application of the spectacles. Further, use of a head tracking system disadvantageously increases the cost as a whole and requires a long measurement period.